1. Field of the Invention
The present invention relates to an image reading apparatus configured to feed, to an image reading portion, sheets supported on a supporting portion one by one to read an image on each of the sheets.
2. Description of the Related Art
In general, a copying machine including an automatic document conveying apparatus (an automatic document feeder) (hereinafter referred to as “ADF”) for automatically reading a plurality of documents (sheets) is widely known. The ADF is configured to separate documents placed on a document tray into each document, convey each document to a reading position, and scan an image of each of the conveyed documents so as to automatically obtain image data of each of the documents.
The above-mentioned ADF which includes a detecting sensor configured to detect the presence/absence of a document on the document tray (document table) has conventionally been devised (see Japanese Patent Application Laid-Open No. 2006-052082). In the ADF described above, in general, documents having the same width are placed on the document tray and are then conveyed to the reading position. However, there is a request to automatically read an image on each of documents of a sheaf of documents having different widths placed in a mixed manner by using the ADF.
In general, the sheaf of documents is placed on the document tray, and the position of the documents is regulated by regulation plates in the ADF. When the documents having different widths are placed in a mixed manner on the document tray, however, the positions of the regulation plates are adjusted to the document having the largest size. Therefore, for the documents having smaller sizes, only one edge is regulated by the regulation plates. In this case, when a difference between the widths of the documents placed in a mixed manner is large, there are some cases where only the documents having a predetermined size or larger can be detected.